Thank you for saving this little guy! If you are having difficulty finding a vet for nail trims a lot of the rabbit rescue groups do free nail trims. They are usually really good about helping when they can.
Here is some good info from the House Rabbit Society on fleas. hope it helps!
Fleas and Mites
Safe treatments to prevent and kill fleas on rabbits include Advantage (imidocloprid), Program (lufenuron) and Revolution (selamectin). The latter is preferred, as it is also effective against various types of mites that cause symptoms of mange, ear canker, and "dandruff" (which is often caused by fur mites in the genus Cheyletiella). These products are available from your rabbit-savvy veterinarian, who can explain dosage and treatment regimens to you at the time of prescription.
A flea comb is a non-toxic device that takes more patience, but is both physically and psychologically rewarding. Most rabbits learn to love the attention of being flea combed, and it can be used as a supplement to your main flea-control program.
The following products should NOT be used on rabbits:
Frontline (fipronil) has been linked to neurological damage and death in rabbits, although this product is apparently safe for dogs and cats. The manufacturer (Merial) has placed a warning on the Frontline label stating that Frontline should never be used on rabbits.
Flea powders, even those considered safe for cats and kittens or advertised as "rabbit safe", are not recommended for use on rabbits.
Flea shampoos, even those considered safe for cats and kittens or advertised as "rabbit safe", are not recommended for use on rabbits. Bathing of rabbits, in general, is strongly discouraged because the stress of the bath itself can cause serious health problems, and has in some cases been linked to the death of the rabbit. Flea baths or dips are NOT recommended for this reason.
For environmental flea control, sprays and "bombs" are not recommended, as they may leave harmful residue that the rabbit can ingest. Safer alternatives include borax and diatomaceous earth, worked into the carpet where fleas leave their eggs.
Here is a really good article on shy bunnies:
http://www.bio.miami.edu/hare/shybun.html
Thanks again for helping this bunny and for understanding what he has been through. I just know he will blossom into a wonderful bun when he learns to trust you!